Stemcell launches instances in EC2. These instances are created to your specification, with knobs like AMI, instance type, and region exposed. The instances are bootstrapped with chef-solo, using a specified git repo and branch as the source of roles and recipes.
Add this line to your application’s Gemfile:
And then execute:
Or install it yourself as:
$ gem install stemcell
Or build the gem locally and install it:
$ gem build stemcell.gemspec $ gem install ./stemcell-0.4.3.gem
If you’re using the command line tool, you’ll need to add a
stemcell.json to the root of your chef repo. It contains default attributes for launching instances as well as the mapping from backing stores to images. For an example, see
You should create an RC file for stemcell with your standard options (and place it in the root dir as .stemcellrc?). You can see an example in
examples/stemcellrc. As documented in that file, you will need:
$ source ~/.stemcellrc
$ stemcell $your_chef_role --git-branch $your_chef_branch
This will cause instance(s) to be launched and their ip’s and instance id to be printed to the screen.
$ stemcell --help
$ stemcell $your_chef_role --tail
To terminate, use the necrosis command and pass a space seperated list of instance ids:
$ necrosis i-12345678 i-12345679 i-12345670
This README presents
stemcell as a tool for administrators to use to create instances. However, we designed
stemcell to be easily useful for automated systems which control server infrastructure. These automated systems can call out to
stemcell on the command-line or use the ruby classes directly.
There are a few additional tools which bootstrap EC2 instances with chef-solo. If you’re using chef-server, obvious answer is knife-ec2. Unless you’re working on a big team where lots of people edit cookbooks simultaneously, we strongly recommend this approach! It’s especially excellent when paired with hosted chef, which makes getting off the ground with configuration management fast and easy.
Finally, we couldn’t resist doing a bit of code archeology. People have been using chef with EC2 for a long time! One early article is this one, which isn’t even on the web anymore. However, it’s spawned some recently-active tools like this and this. Similar approaches are mentioned here, with code here or here (with accompanying blog post) This article, also mentions many worthwhile predecessors.